Research And Verification Of Data Link For Low Rate Millimeter Wave Communication

Data link is a kind of data communication link system which is used to link the information platform on the battlefield.The role data link plays in the modern communication system is getting more and more important,and it get a rapid development.At present,the key techniques of data link include high rate information transfer,low delay,high-capacity,anti-interference,high confidentiality and so on.In this paper,the tactical data link technology is used as a reference to study the physical layer technology of low rate millimeter wave communication digital link.Based on the analysis about the whole design goal of low rate millimeter wave communication digital link,the physical layer transmission scheme which contains the bandwidth of 1MHz,the longest communication distance of 220 km,error rate below 10-6 and the communication link at a speed of 500 bps is designed.Firstly,in order to solve the problem that the frequency of the FPGA is limited by the frequency of the clock in the up and down conversion module,a method of polyphase digital filter is presented.Under the condition that the FPGA clock frequency is 250 MHz,the digital signal is up sampled into the 2.4Gsps sampling rate from the 300 Msps sampling rate in a polyphase manner(decimation is opposite).Secondly,in the design of carrier synchronization module,the two schemes,frequency offset estimation based on fast fourier transform and PLL carrier synchronization,are simulated respectively.Under the AWGN channel,the signal to noise ratio is-16 dB,the Doppler frequency shift is 90 kHz,the bit error rate of the PLL carrier synchronization scheme meets the demand index,while the frequency offset estimation scheme based on the fast Fourier transform does not achieve the bit error rate index.After the implementation of low rate millimeter wave communication data link,the field tests are carried out,including bit error rate test,phase locked loop carrier synchronization error test,and test results to verify the feasibility of the design scheme.